The use of dies with die attach films (DAF) transported on a base material carrier tape to provide direct bonding of dies to a die pad is well known in the microelectronics industry. On picking up a singulated die from the carrier tape, an adhesive layer is carried on a lower surface of the die and, after placing the die on a die pad, the adhesive layer is cured by heating to adhere the die to the die pad. A cross-section of such a structure 10 of a wafer 11 mounted on a DAF adhesive layer 12 and carrier base 13 before dicing is shown on FIG. 1. The wafer 11 and the DAF 12 are singulated to form a singulated die and DAF 15, as shown in FIG. 2, as in dicing a wafer without a DAF, by cutting a channel 14 through the wafer and DAF and leaving a shallow trench 16 in the base film carrier tape 13.
Known dicing of a wafer with a DAF uses a mechanical saw but using higher speed revolution of a dicing saw blade than used to dice a wafer without a DAF, to avoid the adhesive layer adhering to the saw blade. However, such high-speed mechanical cutting tends to cause delamination of the DAF and base film and to create burrs, resulting in yield loss. Burrs created by the mechanical saw can be millimeter long strands of the adhesive layer. These strands may come into contact with an upper surface of the die, either by being carried to the upper surface by the saw blade or in subsequent handling and, in particular, may interfere with a die attach process. In some cases, adhesive is placed on individual die after mechanical saw dicing in order to avoid the problems associated with delamination when using a DAF and creation of burrs. This process is extremely time consuming and inefficient.
It is an object of the present invention at least to ameliorate the aforesaid difficulties in the prior art.